Lake Powell was created by damming the Colorado River with the Glen Canyon Dam, so it is sort of like flooding the Grand Canyon. There has been a drought in the area for a while, so the canyon walls have a bathtub ring about 20 ft. in height.
The scenery was normal spectacular. We could see the lake from our campsite. The tour through Antelope Canyon (the easier, flat tour), was really nifty - the camera saw colors I didn't really see, and we were very lucky to see the sun beams coming down to the canyon floor. The guides threw sand into the path of the beams to better define them.
The boat tour to the Rainbow Bridge was very cool and there was lots of varied scenery. The arch itself was huge, and the walk to it featured some nice water reflections and sandstone formations.